Related Experiment Videos
Thrombospondin is a substrate for blood coagulation factor XIIIa
Biochemistry
|September 23, 1986
Summary
Factor XIIIa (plasma transglutaminase) cross-links thrombospondin (TSP) to itself and fibrin. This ligation, involving TSP
Area of Science:
- Biochemistry
- Hematology
- Molecular Biology
Background:
- Thrombospondin (TSP) is released from activated platelets and interacts with fibrin.
- Platelet activation involves TSP binding to platelet surfaces and copolymerization with fibrin.
Purpose of the Study:
- To investigate the action of factor XIIIa (plasma transglutaminase) on thrombospondin (TSP).
- To elucidate the role of TSP in factor XIIIa-catalyzed cross-linking reactions within fibrin clots.
Main Methods:
- Factor XIIIa catalyzed incorporation of [14C]putrescine into soluble TSP.
- Proteolytic digestion of labeled TSP to identify factor XIIIa reactive sites.
- Analysis of TSP ligation in fibrin clots formed from amidinated fibrinogen.
Main Results:
- Factor XIIIa catalyzed TSP ligation to itself and fibrin intermediates.
- Labeled fragments indicated multiple factor XIIIa reactive glutaminyl residues across TSP domains.
- TSP's disulfide-bonded core copolymerized with fibrin but showed reduced ligation compared to intact TSP.
Conclusions:
- TSP contributes both glutaminyl and lysyl residues to factor XIIIa-catalyzed cross-linking.
- Factor XIIIa-mediated cross-linking of TSP is crucial for stabilizing interactions in hemostatic plugs.